pvlib.irradiance.gti_dirint

pvlib.irradiance.gti_dirint(poa_global, aoi, solar_zenith, solar_azimuth, times, surface_tilt, surface_azimuth, pressure=101325.0, use_delta_kt_prime=True, temp_dew=None, albedo=0.25, model='perez', model_perez='allsitescomposite1990', calculate_gt_90=True, max_iterations=30)[source]

Determine GHI, DNI, DHI from POA global using the GTI DIRINT model [1].

Warning

Model performance is poor for AOI greater than approximately 80 degrees and plane of array irradiance greater than approximately 200 W/m^2.

Parameters:
  • poa_global (array-like) – Plane of array global irradiance in W/m^2.
  • aoi (array-like) – Angle of incidence of solar rays with respect to the module surface normal.
  • solar_zenith (array-like) – True (not refraction-corrected) solar zenith angles in decimal degrees.
  • solar_azimuth (array-like) – Solar azimuth angles in decimal degrees.
  • times (DatetimeIndex) – Time indices for the input array-like data.
  • surface_tilt (numeric) – Surface tilt angles in decimal degrees. Tilt must be >=0 and <=180. The tilt angle is defined as degrees from horizontal (e.g. surface facing up = 0, surface facing horizon = 90).
  • surface_azimuth (numeric) – Surface azimuth angles in decimal degrees. surface_azimuth must be >=0 and <=360. The Azimuth convention is defined as degrees east of north (e.g. North = 0, South=180 East = 90, West = 270).
  • pressure (numeric, default 101325.0) – The site pressure in Pascal. Pressure may be measured or an average pressure may be calculated from site altitude.
  • use_delta_kt_prime (bool, default True) – If True, indicates that the stability index delta_kt_prime is included in the model. The stability index adjusts the estimated DNI in response to dynamics in the time series of GHI. It is recommended that delta_kt_prime is not used if the time between GHI points is 1.5 hours or greater. If use_delta_kt_prime=True, input data must be Series.
  • temp_dew (None, float, or array-like, default None) – Surface dew point temperatures, in degrees C. Values of temp_dew may be numeric or NaN. Any single time period point with a temp_dew=NaN does not have dew point improvements applied. If temp_dew is not provided, then dew point improvements are not applied.
  • albedo (numeric, default 0.25) – Surface albedo
  • model (String, default 'isotropic') – Irradiance model.
  • model_perez (String, default 'allsitescomposite1990') – Used only if model=’perez’. See perez().
  • calculate_gt_90 (bool, default True) – Controls if the algorithm evaluates inputs with AOI >= 90 degrees. If False, returns nan for AOI >= 90 degrees. Significant speed ups can be achieved by setting this parameter to False.
  • max_iterations (int, default 30) – Maximum number of iterations for the aoi < 90 deg algorithm.
Returns:

data (OrderedDict or DataFrame) –

Contains the following keys/columns:

  • ghi: the modeled global horizontal irradiance in W/m^2.
  • dni: the modeled direct normal irradiance in W/m^2.
  • dhi: the modeled diffuse horizontal irradiance in W/m^2.

References

[1]B. Marion, A model for deriving the direct normal and diffuse horizontal irradiance from the global tilted irradiance, Solar Energy 122, 1037-1046. DOI: 10.1016/j.solener.2015.10.024